Marine Sciences and Technology Masters Theses CollectionCopyright (c) 2016 University of Massachusetts - Amherst All rights reserved.http://scholarworks.umass.edu/marine_theses
Recent documents in Marine Sciences and Technology Masters Theses Collectionen-usWed, 09 Nov 2016 01:41:33 PST3600Spatial Ecology of Great Barracuda (Sphyraena barracuda) around Buck Island Reef National Monument, St. Croix, U.S.V.I.http://scholarworks.umass.edu/masters_theses_2/396
http://scholarworks.umass.edu/masters_theses_2/396Wed, 13 Jul 2016 07:38:56 PDT
Marine protected areas (MPAs) are increasing in popularity as a tool to manage fish stocks through conservation of entire habitats and fish assemblages. Quantifying the habitat use, site fidelity, and movement patterns of marine species is vital to this method of marine spatial planning. The success of these protected areas requires that sufficient habitat is guarded against fishing pressure. For large animals, which often have correspondingly large home range areas, protecting an entire home range can be logistically challenging. For MPAs to successfully protect large top predator species, it is important to understand what areas of a home range are especially important, such as breeding and feeding grounds. New technologies, such as acoustic telemetry, have made it possible to track marine animal movements at finer spatial and temporal scales than previously possible, better illuminating these spatial use patterns. This study focused on the movement patterns of great barracuda (n=35), an ecologically important top predator, around Buck Island Reef National Monument, a no-take MPA in St. Croix, U.S.V.I. managed by the National Park Service. As developing standardized methods for acoustic telemetry is still a work in progress, the first half of this study focuses on determining appropriate tools for generating home range size estimates for great barracuda and analyzing ecological parameters driving these results. The second half of this study focused on the use of network analysis to look at spatial divisions within individual home ranges and to compare individual to population level spatial patterns, as well as to generate a relative estimate of population density within the park. Barracuda within the park demonstrated high site fidelity to individual territories, but at the population level they consistently used all habitats within the array. Core use areas within home ranges were evenly distributed throughout all habitats monitored by the acoustic array, although movement corridors were detected along high rugosity reef structures. Greater population densities within the park indicate that density dependent behaviors may be influencing habitat use within the park, and suggest that barracuda are contributing high levels of top down pressure through predation within the park boundaries.
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Becker, Sarah L.Movement Patterns and Catch-and-Release Impacts of Striped Bass in a Tidal Coastal Embayment in Massachusettshttp://scholarworks.umass.edu/theses/1205
http://scholarworks.umass.edu/theses/1205Mon, 17 Mar 2014 08:55:19 PDT
An investigation into the spatial ecology and effects of catch-and-release angling on the physiology and behavior of striped bass was conducted. Fine-scale behavior was assessed by tagging fish with acoustic transmitters equipped with pressure and tri-axial accelerometer sensors and tracking them within a fixed array (n=34 receivers) in a Massachusetts estuary. Activity space changed significantly over the course of the season and increased with water temperature. Striped bass most frequently exhibited low levels of locomotory activity representing 67% of total activity measurements, with occasional high activity and burst swimming, often within the upper 3 m of the water column. Depth distribution of striped bass remained shallower when temperatures peaked at over 21 oC. Diel vertical migration was present with shallowest depths observed during the day and greatest depths during high tide. To investigate catch-and-release consequences, 102 striped bass were angled and blood sampled between July and November 2011. A subsample of 35 striped bass (July n=11, August n=11, September n=13) were implanted with tri-axial acoustic accelerometers to assess relative behavior and survival post-release. Results from principle component analyses produced five factors describing 72.7% of the variance for blood physiology parameters, total length, and water temperature. Subsequently, only eigenvalues from PC1, with high loading for blood lactate, plasma sodium and chloride, and total length, were significantly correlated with fight time. Eight individual fish were detected within 12 hours of release and exhibited their greatest mean daily activity space estimate within that time (1.5 km2 ± 0.6, 50%; 5.6 km2 ± 2.2, 95%). Depth ranged from 0-6.15 m (1.89±1.3 m) and acceleration ranged from 0.095-3.51 ms-2 (0.95±0.33). In summary, no observed mortality suggests that fish were able to recover from the physical and physiological impacts of angling. This thesis has increased the understanding of striped bass ecology and will help promote future conservation and management initiatives for striped bass and facilitate additional research.
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Tyrrell, Heather M.Movement Patterns of Brook Trout in a Restored Coastal Stream System in Southern Massachusettshttp://scholarworks.umass.edu/theses/1199
http://scholarworks.umass.edu/theses/1199Mon, 17 Mar 2014 08:50:00 PDT
Populations of anadromous brook trout can be found from northern Canada into New England. It is believed that the extent of anadromy exhibited by coastal brook trout populations decreases with latitude, but the ecology and movements of the more southern populations are less studied. A 33-month acoustic telemetry study of anadromous brook trout (Salvelinus fontinalis) was conducted in a restored coastal stream and adjacent marine system in southeastern Massachusetts. Movement and migration patterns of 54 brook trout were investigated for individual differences and common features. Individuals exhibited a range of movement patterns. Some were more resident and only moved short distances, while others moved great distances covering the entire stretch of the stream (7.25 km) and moving into the marine environment. General Additive Mixed Models revealed that date was the major influence on brook trout movement between habitats and predicted peaks in movement in the spring and fall. Downstream movement peaked in the spring and in the fall, suggesting post-spawning feeding migration. Fish transitioned between habitats more often at new and full moons and when stream temperature was between 8 and 12 °C. Upstream transitions peaked as temperatures declined in winter 2011. Fifty percent of tagged brook trout were detected in the estuary during the study, suggesting that it is an important habitat for the population. In summer 2012, 14 tagged brook trout (20% of active tags) resided near one receiver at the head of the tide, which contained a thermal refugium in the form of a cold-water spring seep. Of the 84 tagged brook trout, 9.5% moved to the marine environment. Warm temperatures in saline Buttermilk Bay in the summer and cold temperatures in winter probably discourage some individuals from entering the marine environment. Compared to more northern coastal populations of brook trout, the Red Brook population appears to be less anadromous.
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Snook, Erin L.Habitat Heterogeneity Concentrates Predators in the Seascape: Linking Intermediate-Scale Estuarine Habitat to Striped Bass Distributionhttp://scholarworks.umass.edu/theses/1050
http://scholarworks.umass.edu/theses/1050Mon, 29 Jul 2013 09:40:30 PDT
Predators are key components of aquatic ecosystems and innovative approaches to understanding their spatial distribution are imperative for research, effective management, and conservation. Discontinuities, created by abrupt changes between two unlike entities, are irregularly-distributed, intermediate-scale features that can have a disproportionate effect on organismal distribution within the seascape. Here I use the discontinuity concept to relate the distribution of a predator, striped bass (Morone saxatilis), to physical features within Plum Island Estuary (PIE), MA. I mapped the distribution of 50 acoustically-tagged striped bass during four monthly surveys at 40 sites to evaluate if heterogeneity in physical features concentrated predators. All striped bass survived tagging, were coastal migrants, displayed seasonal residency within PIE, and moved freely throughout the estuary. However, these highly mobile predators were not evenly distributed. Specifically, striped bass were clustered in the middle region of PIE in response to sandbar area, intermediate bottom unevenness, channel networks, and, to a lesser extent, confluences and drop-offs. The highest predator counts occurred at sites with the greatest additive habitat complexity. I measured 23 geomorphic metrics at 40 sites within the seascape to characterize the spatial patterns of confluences, drop-offs, bathymetry and land features. Then, I mapped integrated measurements of multimetric physical features to reveal distinct spatial trends in physical complexity of the estuary. By expanding the discontinuity concept and combining irregularly-distributed, intermediate-scale physical features with smaller-scale, traditional fish habitat methodologies, I revealed consistent and ecologically-meaningful patterns within a north temperate estuarine seascape.
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Kennedy, CristinaHeavy Metal Food Chain: Relating Feeding Ecology and Mercury Bioaccumulation in Southern New England's Top pelagic Predatorshttp://scholarworks.umass.edu/theses/956
http://scholarworks.umass.edu/theses/956Fri, 23 Nov 2012 07:53:21 PST
Mercury accumulation of upper trophic level marine fishes is a growing concern for human consumers. Diet is the primary source of mercury bioaccumulation in both fish and humans and yet remains unexamined in many intensely fished regions such as southern New England (SNE). The feeding ecology and mercury concentrations of recreationally caught albacore (Thunnus alalunga) and yellowfin (T. albacares) tunas, shortfin mako (Isurus oxyrinchus) and common thresher (Alopias vulpinus) sharks and dolphinfish (Coryphaena hippurus) were evaluated. Important prey were identified and also measured for total mercury content. Seventy percent of the predator fishes sampled in this study had mercury concentrations greater than the EPA recommended 0.3ppm, and included shortfin makos (2.65 ± 1.16ppm), threshers (0.87 ± 0.71ppm) and albacore (0.45 ± 0.14ppm). Mercury concentrations were lowest in dolphinfish (0.20 ± 0.17ppm) and yellowfin (0.32 ± 0.09ppm). Length was positively correlated with mercury content and bioaccumulation rates were linear for tunas and dolphinfish, while exponential for both shark species. Small schooling fishes (Pomatomus saltatrix, 0.110 ± 0.102ppm) were the primary prey of shortfin makos. Shortfin squid (Illex illecebrosus, 0.028 ± 0.005ppm) was a principal and consistent dietary component of both tunas and dolphinfish diets. The diets of SNE dolphinfish and yellowfin tuna were more invertebrate dominated than other regions previously examined. Though the method of sample collection for this study biases toward larger individuals, these are the sizes of fish targeted by anglers, generally for human consumption.
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Teffer, Amy K.Distribution Patterns of Migratory Striped Bass in Plum Island Estuary, Massachusettshttp://scholarworks.umass.edu/theses/209
http://scholarworks.umass.edu/theses/209Wed, 21 Jan 2009 12:07:21 PST
This is the first study to assess how the coastal migratory stock of striped bass (Morone saxatilis) uses non-natal New England estuaries during their foraging migration. Using hydroacoustic telemetry from June through October in Plum Island Estuary, Massachusetts, I examined how long coastal migratory striped bass stayed throughout the seasons, if they were equally distributed, if individual striped bass were distributed differently, and if distribution changed with season, tide, or light. Striped bass, ages 2-5 (300-480 mm), were tagged with VEMCO transmitters in the spring and summer of 2005 (N=14) and 2006 (N=46). They stayed for an average of 66 days in 2005 (SE=7.6) and 72 days in 2006 (SE=6.2). Of the fish tagged in 2005 and 2006, 60% remained for longer than 30 days. This might reflect two striped bass migration strategies: 1) transient migration, in which striped bass visit many estuaries, and 2) estuary-specific, in which they reside in a single location for the summer. The amount of time the striped bass spent in six reaches delineated within the estuary was quantified. Striped bass were not evenly distributed across these reaches. Instead, they spent the most time in the mid Plum Island Sound and lower Rowley River reaches in both years. Three different uses of PIE were observed. Some striped bass stayed briefly (5-20 d; N=24), some stayed primarily in the Rowley River (N=14), and others stayed primarily in Plum Island Sound (N=22). Striped bass use of the mid Plum Island Sound and lower Rowley River reaches remained consistently high in spring and summer, but decreased in fall, while use of the lower Plum Island Sound did not vary much. Use of other reaches varied seasonally. Tide and light were less associated with distribution, but in the summer the Rowley River use-group increased utilization of tidal creeks during the day, though not at high tide. These three use-groups identified in Plum Island Estuary may be foraging contingents that may learn how to forage in specific parts of the estuary demonstrated by over half the striped bass remaining for much of the summer and congregating in distinct areas.
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Pautzke, Sarah M.